Apparatus for drying air



May 1, 1945.

C. E. BENNETT ET AL APPARATUS FOR DRYING AIR Filed July 3, 1942 ATTORNEY Patented May ll, 1945 APPARATUS Fon DRYING Am Charles E. Bennett, Ridgewood, and Paul V.

'White, Rochelle Park, N. J., assignors to The' e OkonitefCallender Cable Company, Incorporated, Paterson, N. J., a corporation of New Jersey Application July 3, 1942A, sena; No. 449,512

" 1 claim. (ci. cs2-4.135)

Our invention isdirected to improvements in air drying equipment, and has for some of its objects the provision of a method of and appa- Y ratus for drying air which is relativelyinexpensive to install and operate, remarkably rapid and efficient in operation and which can be operated continuously when desired over'extended periods of time.

'I'he inventionis adapted for many uses, in tact for all uses practically where dry air is to be supplied continuously or intermittently as desired.

One held for which our .invention is particularly well adapted, however, is in the drying of pipe lines of electric cable systems. A well known type of yelectric cable system comprises a relatively large metal pipe line into which the cableconductors, sheathed in oil .permeable material high as say one hundred and flftygpounds per condensing out of the air to be processed on its passageto the drying chamber. The air to be dried is compressed appreciably by the compressor 4 and as a result considerable moisture is removed in the extractor 8 before the partially The dried air goes into the drying chamber 2. compressor I places'the air under aI pressure as square inch. This eiects a 'concentration of the moisture contained in the ,air so that considerable moisture will be precipitated in the e'xtractor 8.

The drying chamber 2-, as illustrated, takes the form of an elongated closed tank. Within the drying chamber and extendingpractidallytm lengthv of the same is a. cooling coil IU, a suitable4 coolant such as any of the well known refrigsuch as paper insulation, are drawn. The pipe line is then filled' with oil which is thereafter maintained at superatmospheric pressure. It is essential that this pipe line be thoroughly dry before the conductors and oil are placed therein, the presence of water, even although in minute quantities, eventually 'causing breakdown.

The present invention is ideal in this connection inasmuch as 'the dried air as it is being provduced by our method and equipment .can be passed continuously through the pipe line and the air beingin a thoroughly dry condition is highly hygroscopic and will readily take up any moisture Within the pipe line. This very materially speeds up installation of the cable system thereby eiecting appreciable savings in installation costs, with the production of a much more perfect job.l Under present methods of installing these systems it is customary to drag cloth swabs through the pipe line and to pass heated air through the line. By such methods it does not appear to be possible thoroughly to dry the line. The swabs cannot reach and remove all of the water deposited in and 'on the walls of the pipe line, while moisture contained in the heated air condenses out as the hot air strikes the relaf` tively cool walls o! the line.

An embodiment of'our invention has been illustrated in part sectional elevation in the accompanying drawing.

Referring to thecrawing in detail: rn the em# bodiment illustrated, our invention comprises an air drying. chamber 2 to which air Is supplied by air compressor 4 when our apparatus is in operation. In the line 8 leading from theTcompresser to the bottom of the drying chamber we provide water extractor 8 to catch the moisture erants being circulated through this cooling coil by refrigerating unit I2.

Packed aboutthe coil I0 is a suitable heat conducting material such as metal wool,'bronze wool, Vfor instance, which we have designated I4. The capacity of the cooling coil is suilicient to maintain the wool Il at a temperature at least as low as the dewpoint of any moisture entrained in the air being processed.

yLeading from the top of the drying chamber 2 isvoutlet or discharge pipe I6. In this line we provide an Aridier. I8, which may be of-the well known commercial type, the processed air passing out of the top of the Ariciiiler'to use. For example, inV installing a cable system such as that above referred to, theV dried air as itdischarges from, the Ardiiier I8 is passed directly into the pipe line to be dried. K i

Traps 20 -are 'provided for the moisture taken out'of the air in its passage through the extractor 8 and the drying'chamber 2, while an- .other trap 22 i's provided for moisture extracted by the Aridiiier I8. These traps, are all co veniently connectedA to a water drain line 2|.

In operation the air to be dried is maintainedunder pressure in the compressor tank 24, the pressure employed being of the order of lbs. per sq. in. With the refrigerating unit -I 2 and Aridifier I8 in operation,'the valve 26 in the discharge line from 'the extractor 8 is cracked to allow the compressed air to expand into the drying chamber. By compressing the air, consider- `able moisture is removed therefrom lbefore it r passes to the drying chamber 2, because of moisl vo. f C

ture concentration due to the 10:1, for example, reduction in volume of the air. As Athe compressed, partially driedair expands into the drying chamberZ toward the outlet thereof it must pass through the voids in the wool mass I4. This wool, as above pointed 'out is chilled by the cooling coil I0 to a temperature at least as low as the dewpoint of any moisture remaining entrained in the air, so that this moisture will condense and be deposited upon the wool. Any traces of moisture remaining in the processed air as it leaves the drying chamber is removed by the Aridier I8 and the now thoroughly dry air may then pass by conduit 28 into and through a pipe line which is to be dried as above explained, or to any other use desired.

From time to time the equipment may be shut down to permit of the moisture removed from the air to be drained oif at the traps 20 and water drain line 2l.

From all of the foregoing it will be seen that we have provided an exceedingly simple process and apparatus for drying air, which is rapid and elcient in operation, which does not deteriorate or lose its effectiveness in use, and which may be operated over long periods of time.

It is to be understood that changes may be said air-drying tank, and metal wool packed about said refrigerating coils, the capacity of the refrigerating coils being such as to maintain the metal wool at a temperature at least as low as the dewpoint of any moisture entrained in the air suppliedl to the air-drying tank from the com pressed air tank so that this moisture will condense and deposit upon the wool, and an outletl from the air-drying tank for the passage of the processed air to a pipe to be dried.

CHARLES E. BENNETT. PAUL V. WHITE. 

